It is commonly understood in the food service industry that reconstitution of powders creates certain problems not encountered during typical reconstitution of dehydrated products. In food service dispensing such as point of sale coffee machines or the like, the products need to be mixed quickly as time and temperature are limiting factors. Currently, whipper/mixing bowl assemblies are commonly used for mixing/frothing during dispensing. However, such assemblies have certain disadvantages: (i) powders may stick to many dead spots and compromise safety due to related bacterial growth; (ii) there is more wear and tear due to moving parts; (iii) there is damage to particulates from excess contact with such moving parts; and (iv) increased costs associated with use of such assemblies. Moreover, the quality of froth is often perceived to be lower from a whipper/mixing bowl assembly. Another limitation of existing mixing/frothing systems relates to the dispensing time and temperature of the final delivered food. For instance, for large volumes of beverages, such as 250 mL or more, the delivery time is far too long, as the water flow rate must be maintained slow so that an efficient mechanical mixing and frothing can be carried out. Prolonged delivery times of beverages are not well accepted by end-users. Furthermore, the delivery of cold or ambient liquid food from powder creates dissolution problems as powder poorly dissolves with ambient or cold water.
One commonly known type of dispensing system uses an impeller driven by an electric motor that mixes powder with water in a mixing bowl. This system requires frequent cleanings and may have some negative hygienic issues related to residual product left in the mixing container. When using powders, precipitation of non-dissolved powder particles as well as stratification of liquids may occur in the container—e.g., a cup or bowl—after dispensing. Further, considerable maintenance may be required for the mixing container and the impeller motor. Moreover, currently only liquid milk is used to produce steam froth. Liquid milk, as opposed to powder, has disadvantages in handling such as shelf life, the need for refrigeration, and hygienic concerns.
Consequently, it is desirable to have a more efficient, compact, hygienic, relatively low cost solution to deliver uniform high quality steam foam or foamed beverages—e.g., milk froth—through dispensing of powder ingredients without the use of a motorized whipper.
Certain whipperless systems are taught in the prior art. WO 02/087400 to Hayes et al. and WO 03/041506 to Charman describe methods of producing foamed beverages including the steps of providing a capsule containing a powder, injecting water into the capsule to mix with the powder, allowing the resultant mixture to escape into a receptacle, and injecting water into the receptacle by way of a jet to produce a foamed liquid in the receptacle. Hayes et al. and Charman do not teach intersecting streams of powder and liquid.
U.S. 2003/0089244 to Imboden et al. describes an assembly for generating milk foam and for heating milk. A mixing element receives, in order, a first stream of steam, air, a second stream of steam, and liquid milk. The starting material is liquid milk, rather than a powder.
U.S. Pat. No. 5,335,588 to Mahlich describes a device for preparing milk froth for cappuccino. The device comprises a steam inlet and an air inlet that lead through a Venturi to an opening. The opening is submerged in liquid milk, for instance in a cup, such that the steam, air, and milk are mixed to create foamed milk. This method is known as “in-cup frothing.” The starting material is liquid milk, rather than a powder. Similarly, FR 2 745 485 to Jorge also relates to in-cup frothing with liquid milk, rather than a powder.
U.S. Pat. No. 6,681,685 to Mahlich describes a device for preparing milk froth for cappuccino. The device first mixes liquid milk and air. This mixture is then fed into an area into which steam is output. The starting material is liquid milk, rather than a powder.
U.S. Pat. No. 5,884,552 and U.S. Pat. No. 6,253,667 to Lüssi et al. describe an emulsifier for preparing frothed milk and hot milk. Liquid milk is first mixed with air. This mixture is then mixed with steam. Optionally, the mixture is mixed with coffee.
U.S. Pat. No. 6,183,800 to van Straten et al. describes a method for preparing milk or café crème. Water is introduced into a Venturi container causing coffee concentrate or liquid milk concentrate to be sucked in. The water and coffee concentrate then flow to a whirl container for mixing and dispensing.
EP 0458310 to Vogt et al. describes a foaming coffee whitener that produces a foamed cappuccino-like beverage. Frothing via such a whitener is generally considered inferior to pressure-based frothing.
WO 02/100224 to Wessels et al. discloses an apparatus for preparing a beverage with a foam layer. The apparatus includes a whirl chamber that combines a liquid concentrate with steam to produce a foam layer.
EP 1,348,364 to Vittecoq describes an apparatus for mixing and foaming a powder-based beverage with at least two jets directed in a cup either simultaneously or alternatively, at different orientations and different heights, and without rotating the cup. Vittecoq does not teach intersecting streams of powder and liquid.
U.S. Pat. No. 4,388,338 to Wittenborg describes a method and device for preparing powder-based beverages including multiple streams. A pre-measured amount of powder is filled in a cup and the cup is partially filled with a first quantity of water via a low velocity stream. Subsequent stream(s) are provided at higher velocities to whip the beverage. Such a system would tend to exhibit residual unmixed powder that may collect at the bottom of the cup during the low velocity stage.
It is desired to provide a method and apparatus to pre-wet consumable powder by a liquid to overcome the undesirable characteristics, drawbacks, and disadvantages of the systems currently used. It is also desired to provide a method and apparatus to deliver more quickly and efficiently high quality frothed beverages obtained by reconstitution from a powder.